Cellulose films



I (No Model.) 3 Sheets-Sheet 1.

' J WILLIAMS PROCESS OP PRODUGING CELLULOSE FILMS.

Patented Jan. 13,1891.

/VVzeJJ- 3 sheetssheet 2.

(No Model.)

J WILLIAMS PROCESS 0F PRODUGING CELLULOSE FILMS.

No. 444,515. Patented Jan. 1s, 1891.

(No Model.) l' 3 Shets--Sheet 3,

J. WILLIAMS. PROCESS OF PRODUGING CELLULOSE FILMS. N0. 444,515.

Patented Jan. 13,1891.

u.. maro-urna., wAsmnnvan u c UNITED STATES PATENT EEicE.

.I AMES VILLIAMS, OF VVILLESDEN JUNCTION, ENGLAND, ASSIGNOR TO THE PATENT WATERPROOF PAPER AND CANVAS COMPANY, LIMITED, OF

SAME PLACE.

PROCESS OF PRODUCING CELLULOSE FILMS.

SPECIFICATION forming part of Letters Patent No. 444,515, dated January 13, 1891.

Application filed January 16, 1890. Serial No.4 337,108. (No specimens.)

To all whom it may concern.-

Be it known that I, JAMES WILLIAMS, chemist, a subject of the Queen of Great Britain, residing at Vilillesden Paper Works, Willesden Junction, in the county of Middlesex,

England, have invented certain new and useful Improvements in Processes of Producing Cellulose Films, of which the following 1s a specification.

1o The object of my invention is to produce an amorphous or struct-tireless film upon the surface of paper or other suitable fibrous fabric or material, which is thus materially strengthened, and may be used for a great [5 variety of purposes 'in the arts. A fabric having such a surface, for instance, may be used as a substitute for the albnmenized paper noWin common use for photographic purposes; or the unchanged portion of the fabric zo may be separated from the cellulose film, which latter, being capable of resist-ing the laction of water, steam, Weak acids, and most solids, may be used for a great variety of purposes. I produce this film by applying a solvent to the surface of the fabric and afterward eliminating the solvent from the film. Ipreferably apply the solvent to one surface only of the fabric, leaving the other surface unaltcred, in contradistinction to the old way of dipping the fabric in the solvent, as such unaltered surface imparts strength to the sheet or fabric, so that it is easier to manipulate it both during and after the process of man ufacture.

I prefer to proceed as follows in carrying ont my invention: I first prepare a bath of strong cuprammonium hydro-oxide solution, which must be of the utmost possible purity,

4o and I find it convenient to use from 1.5 to 2.5 per cent. of metallic copper, according to the degree of brilliancy required. I apply this bath to ne side of the fabric, preferably by ioating its surface thereon, care being taken that one side only of the fabric comes in contact with the solution, by which means I convert such surface into an amorphous, structureless, or approximately structureless film of cellulose, which is combined at this stage with the oxide of copper, ammonia, and water. 5o The fabric is then, with as little exposure to the air as possible consistent with the setting of the film, exposed to heat, which is applied first to the unchanged surface of the fabric to expel the ammonia and water from the deposited film. The fabric thus treated has a green tint, due to the copper hydrate contained in the deposited film. To remove this hydrate, and thus render the fabric suitable for photographic purposes, I apply a weak 6o acid thereto-such as sulphuric acid-which dissolves out the copper without affecting the glazed surface of the film. I prefer several consecutive applications of weak acid, as above described. The fabric is then washed and dried,`and is ready for use.

I separate the film from the unchanged fabric, when desired, by soaking the latter in water in well-known ways, so as to soften it, and thus render it readily removable. 7o

The accompanying drawings represent a vertical longitudinal section through a convenient apparatus for carrying out my invention, the three sheets of drawings representing different portions, which when placed end to end. constitute the complete apparatus, of which- Figure I shows the delivery end; Fig. 2, the central portion, and Fig. 8 the feed end, the fabric under treatment passing from 8o right to left.

The sheet or web of fabric passes from a roll A, between fced-rollers B, over the surface of a bath C of cuprammonium solution, the lower surface of the fabric being drawn along' in contact with the upper surface of the bath. The fabric then passes around a small guide-roller (l and over leading-drums D D,upon which the dry surface of'the fabric rests. Thence it passes round steam-heated 9o cylinders E E2, with the first of which the dry side comes in contact in order to set the film and prevent its adhesion to the second cylinder E2', with which the film or treated side is kept in contact by an endless belt F, 95 traversing suitable rollers, as usual. If not sufficiently dry, the fabric may then pass around a third heated cylinder E3.

'lhe whole apparatus is driven by endless belts in well-known ways to secure uniformity of speed and maintain the necessary slackness throughout, or, in other words, to avoid undue tension on the fabric.

When it is desired to render the film colorless, the fabric on which it has been formed, as above described, is passed through consecutive baths N N of weak acid, passing therethrough under partially-submerged rollers O and around rollers I between each bath.

' The fabric then traverses rollers in a water bath Q, thence over a revolving drum R into other water baths S, in which it is wholly submerged until free of all injurious impurities. The fabric is then taken by a third revolving drum Ri", which need not be heated, around a series of cylinders T T, similar to those already described, and heated in Wellknown ways, which gradually dry the fabric. The film thus treated, as hereinbefore remarked, is capable of withstanding the action of water, steam, weak acids, and alkalies, as well as ordinary solvents. This property enables me to remove the unchanged portion of the fabric, lea-ving only the film of cellulose.

Preferably I remove the unchanged portion of the fabric by washing the fabric in water with an ordinary or a rotary scrubbing-brush, but of course analagous means may be employed.

Having thus f ully described my improvements in the art of producingr cellulose films, what I claim therein as new and as of my invention is- 1. The process hereinbefore described of exposing the fabric to the action of cuprammonium hydro-oxidc to form a film thereon, drying it to remove the amnionia, and then subjecting the fabric to the action of acid to eliminate the copper.

2. The process "hereinbefore described of Heating the fabric u`pon the surface ofasolvent, such. as cuprammonium hydro-oxide, applying heat to the fabric, passing it successively through diluted acid and through water, and again drying it.

3. The process hereinbeforc described of exposing the fabric to the action of the solvent, eliminating the solvent, and then removing the unchanged portion of the fabric from the amorphous film produced by the action of the solvent.

4. The process hereinbefore described of exposing:r the fabric to the action of euprammonium hydro-oxide to form an amorphous iilm of cellulose thereon, then removing the ammonia by drying and the copper by acid, and afterwardremoving the unchanged portion of the fabric.

5. The process herenbeforc described of floating the fabric upon the surface of a solvent, such as euprammonium hydro-oxide, to form an amorphous film of cellulose thereon, heating the fabric, subjecting it successively to the action of acid and to the action of water, again dr 'ing it, and afterward washing off the unchanged portion of the fabric.

JAMES WILLIAMS.

Witnesses:

JNO. H. WHITEHEAD,

2l Sonthmnptoa Buildings, London., IV. C'.

THOS. LAKE,

28 Southampton B11/Zd ings, London, W. O. 

